I have been working to network boot via PXE some older Dell Dimensions. I discovered that older NIC's were not able to take the packet from the DHCP server and find the tftp server (verified this from the vendor, 2X). So, I started to swap out NIC's and try different ones. At some point during all this swapping (I can't really say when), I "lost" the capacity or ability to even do a network boot. It doesn't even appear to go through the device as a boot option any longer. I put Network boot at the top of the list, put the old cards back in, re-flashed the BIOS to the latest versions, removed all other bootable media, etc. I can't even get back to the old broken place i was at, with the MBA starting, but then hanging.
Has anyone ever seen this and fixed it?